Midi Controlled Drum Set

Origins

While at Maker Faire 2007 in Austin with the guys from ArcAttack!, Someone suggested that it would be great to have a drum playing robot to play along with the Tesla coils. That night I searched my usual surplus websites and found some rotary actuators that might be sutiable. I ordered a couple and then thought about ways to drive them.

I had already built the midi controlled pipe organ so some of the work was done. I experiemented over a few weeks with various sticks to attach to the acutators. I don’t have metal working tools so I made various sticks from hardwood. I used Power FET transistors to drive the solenoids and then figured out what the solenoids could handle. If you keep the duty cycle low you can drive the solenoids hard. I cooked a few in the process of building and testing the drum set.

Building It

The first instrument was a snare drum provided by John DiPrima from ArcAttack. I breadboarded a driver and made a lot of noise in the process of testing. I got some good industrial ear protectors from the home center to save my ears. Maker Faire was in October. By February of 2008 I had figured out a way to use PIC microcontrollers to generate the pulses necessary to drive the solenoids. I got some cymbals and a cowbell from a music store then built wood stands to hold the instrumetns and actuators. I used a five gallon plastic paint bucket for a kick drum. I got it done barely in time for the South by Southwest Interactive, Dorkbot Party on March 8th. I hauled it all to the party and John quickly programmed a few numbers before the party started. It worked! It’s really cool when things work!

After that I got the kick drum and toms from John and Joe then thats about when we shot the “Creepy Circus Song” video. (find it in the Gallery) Since then I have made new sticks with aluminum and carbon fiber parts and doubled up two actuators for a more energetic kick drum and added an additional stick for the snare. I also added some LED’s to each instrument to add some flash in the dark. All this you can see in the second prototype video. (also in the Gallery)

There was an intermediate prototype controller that was a bit more durable, then finally the controller we are using now which I built with a complete set of new PC boards for the midi decoder and drivers then enclosed the whole thing in a nice hinged box. The new boards included proper opto-isolation and FET drivers to make sure the FETs were turned on fully.

Now on the todo list: An actuator for the top-hat, clamp-on actuators and a durable and more portable controller.